This invention relates to an improved device for dispensing powder or granulated material for imaging devices such as copiers, facsimile machines, and printers. More particularly, this invention relates to an improved toner cartridge cap that facilitates the conveyance of toner material from a toner cartridge to the developer in an imaging device.
Imaging devices such as photocopiers, facsimile machines, computer printers and the like typically use dry toner particulate material to produce electrostatic latent images. As a result of the continuous dissipation of toner material in this process, the supply of toner to the developer must be rejuvenated on a regular basis. Conventional imaging devices often employ cylindrical containers or cartridges of toner, for example as taught in U.S. Pat. No. 5,774,773. Prior inventions employ a cartridge cap that fits tightly within one end of the toner cartridge, while the outside surface of the cartridge cap extends over the perimeter of the toner cartridge. In these devices, toner is transferred as it is needed to the developer by rotating the toner cartridge, which is typically mounted on its side. As the toner cartridge is rotated in such inventions, a shutter mechanism, which covers a small opening in the cartridge cap, is retracted, allowing toner to flow through the cartridge cap to the developer.
There are certain problems or deficiencies with the design of prior toner cartridge and cartridge cap assemblies. First, prior inventions do not include a method to securely lock the cartridge cap to the toner cartridge. Therefore, an end user can inadvertently dislodge the cartridge cap from the cartridge while removing the cartridge from the imaging device, causing toner to pour out of the cartridge and be lost and dirtying the user and work environment.
Further, prior inventions do not always permit the toner to exit the cartridge at a rate sufficient to ensure proper print quality. Tests have shown that an average of only 0.5 grams of toner can flow through a common cartridge cap per revolution of the toner cartridge when the cartridge contains between approximately 250 and 710 grams of toner. The reduced flow of toner out of the cartridge degrades print quality and/or requires the drive motor which rotates the cartridge to operate more frequently than would otherwise be necessary.
Moreover, prior inventions do not completely prevent the discharge of toner from the cartridge cap once the shutter is moved to the closed position. Because the cartridge cap does not have a sealing mechanism at the point of discharge, toner spills out of the cartridge cap during removal of the toner cartridge. Such spills cause a loss of toner and pollute the machine, the work area, and the user.
Finally, existing designs require two large openings on the tip of the cartridge cap to enable adequate toner flow. These large openings allow dust to escape from the toner cartridge and contaminate the internal mechanisms of the imaging device. The present invention channels the toner through the end of the cartridge more efficiently and prevents the toner from packing around the discharge end of the cartridge. The efficient channeling of the toner through the end of the cartridge then enables the exit holes on the cap to be smaller in size. The reduced size of the exit holes in the configuration of the present invention limits the amount of dusting that might occur in the imaging device while still providing an adequate supply of toner to the developer.
The present invention overcomes the problems and deficiencies of existing toner cartridge and cap assemblies, as described above. It is one object of the present invention to provide a secure means to lock the cartridge cap to the toner cartridge, preventing the end user from inadvertently dislodging the cartridge cap from the cartridge. It is a further object of the present invention to provide a device which can permit toner to flow at a rate sufficient to ensure proper print quality. It is yet another object of the present invention to provide a device which is less likely to discharge toner from the cartridge cap once the cap is moved to the closed position. It is a further object of the invention to provide a device with properly sized openings in the cartridge cap so as to hinder large amounts of dust from escaping from the toner cartridge during normal operations and thereby contaminating the internal mechanisms of the imaging device.
To achieve the above objects, the present invention provides an improved toner cartridge cap that comprises: a base portion with a cylindrical main body forming a hollow chamber and having a first end and a second end and sidewalls that encircle the diameter of the cylindrical main body and at least one collection fin coupled to the cylindrical main body. Once assembled, the collection fin extends into a toner cartridge and facilitates the conveyance of toner material from the toner cartridge through the first end of the cylindrical main body and into the hollow chamber and into an imaging device. In the preferred embodiment of the present invention, the base portion is coupled to a top portion that is comprised of a top-portion cylindrical main body forming a hollow chamber and having an upper end and a lower end, and sidewalls that encircle the diameter of the top-portion cylindrical main body. Additionally, an end piece is extended in the preferred embodiment across the upper end of the top portion. Preferably, there is at least one opening in the sidewalls of the top portion and at least one opening in the sidewalls of the base portion as well.
The present invention also includes a method for facilitating the conveyance of toner material into an imaging device comprising the steps of employing a base portion with a cylindrical main body forming a hollow chamber and having a first end and second end, coupling the collection fin to the cylindrical main body and extending the collection fin into the toner cartridge. In the preferred embodiment of the present invention, the method further comprises the step of employing a top portion with a top-portion cylindrical main body forming a hollow chamber and having an upper end and a lower end and sidewalls that encircle the diameter of the top-portion cylindrical main body wherein an end piece is extended across the upper end of the top portion. Preferably, the top portion and bottom portion each have at least one opening in their sidewalls to facilitate the conveyance of toner.